textproduct: Rapid City

KEY MESSAGES

- Isolated showers/thunderstorms possible later Sat afternoon and evening northeast WY into SW SD

- Increasing temperatures through Memorial Day

- Chances of showers and thunderstorms will return Tuesday night and continue through the rest of the week

UPDATE

Issued at 925 PM MDT Fri May 22 2026

Minor changes to the previous forecast. Limited pops isolated mention Sat afternoon and evening and expanded them west into northeast WY. Steep lapse rates coupled with a weak impulse will be sufficient to support convection with gusty winds possible with any cells. Warmer with highs in the 70s. Otherwise, mainly dry through Tues with warmer temps each day. Staunch SE flow expected Tue, which will bring deeper moisture back into the FA along with low chances for showers/storms.

DISCUSSION

(This Evening Through Friday) Issued at 204 PM MDT Fri May 22 2026

Radar/satellite/surface obs show the stacked low pressure over central SD, continuing to move NE. Behind the low, mid-level clouds have developed within the resulting cold pool. Likewise, KUDX radar shows the stratiform rain this morning becoming more convective showers across eastern Meade/Pennington, and Haakon counties. NW winds over the western SD plains have mostly been gusting up to 40- 45 mph, but we are starting to see occasional higher gusts in the showers...even outside of the Wind Advisory area. Knowing these gusts will be isolated and only through the afternoon...and since gusts are not otherwise reaching advisory criteria, will cancel the advisory early. Winds will weaken this evening and skies will clear overnight. There was some concern about frost developing across the NE WY plains in the early Saturday morning hours. However, with warm air advection moving in and variable winds becoming southwesterly at 5-10mph, think the only places that may see frost develop will be wind sheltered areas/river valleys. And it looks like temps may reach the lower to mid 30s only for an hour or two before sunrise, so will not issue any headlines. The evening shift can take a second look, but as of now, it looks too marginal. Drier weather is expected over the holiday weekend into the first part of next week. The exception is isolated thunderstorms across portions of the Black Hills where there could be enough instability to get a few storms to develop. Severe weather is not expected. Warm air advection through the weekend will bring warmer temperatures each day. The warmest day will be on Memorial day, with highs in the mid 80s to lower 90s across most locations. The second half of next week looks interesting. GFS/ECMWF are showing a Rex Block setting up over the central CONUS. This could bring active southerly flow with decent moisture to the area...which would support showers and thunderstorms.

AVIATION

(For the 12Z TAFS Through 12Z Sunday Morning) Issued At 507 AM MDT Sat May 23 2026

VFR conditions are expected through the period. A weak impulse may generate very isolated shra/TS Saturday afternoon over northeastern WY into the Black Hills and southwestern SD.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.